Đáp án:
Giải thích các bước giải:
`x^4-2x^3+x^2-9`
`=x^2(x^2-2x+1)-(3)^2`
`=[x(x-1)]^2-(3)^2`
`=[x(x-1)-3][x(x-1)+3]`
`=(x^2-x-3)(x^2-x+3)`
`(x+1)(x+2)(x+3)(x+4) - 4`
`=[(x+1)(x+4)][(x+2)(x+3)]-4`
`=(x^2+5x+4)(x^2+5x+6)-4`
Đặt `x^2+5x+5=t`
`=(t-1)(t+1)-4`
`=t^2-1-4`
`=t^2-5`
`=(x^2+5x+5)^2-5`
`=(x^2+5x+5)^2-(\sqrt{5})^2`
`=(x^2+5x+5-\sqrt{5})(x^2+5x+5+\sqrt{5})`
`\qquad x^4-2x^3+x^2-9`
`=x^4-x^3+3x^2-x^3+x^2-3x-3x^2+3x-9`
`=x^2(x^2-x+3)-x(x^2-x+3)-3(x^2-x+3)`
`=(x^2-x+3)(x^2-x-3)`
-------------------------------------------
`\qquad (x+1)(x+2)(x+3)(x+4)-4`
`=(x^2+4x+x+4)(x^2+3x+2x+6)-4`
`=(x^2+5x+5-1)(x^2+5x+5+1)-4`
`=(x^2+5x+5)^2-1-4`
I. Change these questions into passive voice 21. Have the Browns built this large house? → ________________________________________________________________________ 22. Did a jelly fish sting her sister while she was swimming?→ ________________________________________________________________________ 23. Did they give her a nice present? → ________________________________________________________________________ 24. Is Jane singing a new song? → ________________________________________________________________________ 25. Did the storm destroy the house? → ________________________________________________________________________ 26. Does she water the flowers every day? → ________________________________________________________________________ 27. Does the headmaster call his parents to the office? → ________________________________________________________________________ 28. Will Ben direct the show? → ________________________________________________________________________ 29. Had the dog broken the window panel? → ________________________________________________________________________ 30. Were they interviewing her for the job? → ________________________________________________________________________
.Question 1: Brown is _________________tutor in our university. (experienced) Question 2: _________________pupils should be paid more attention. (good) Question 3: _________________film we've ever seen is "Enter the Dragon". (interesting) Question 4: It was Chris who wrote_________________ composition. (brilliant) Question 5: Spring is _________________season of the year. (pleasant) Question 6: Tom's room is _________________of all. (clean) Question 7: Of all Polish writers, Sienkiewicz is _________________one. (great) Question 8: Jim is _________________pupil in my class. (difficult)
Giúp mình câu này với ạ, thanks mn ❤️
Cho a= log2; b=ln2. Hãy biểu diễn ln800 theo a và b.
Hộ mình câu c bài 5 với câu f bài 3 với
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